As soon as Bootcamp landed, I went out & bought Half Life 1, which I'd been wanting to revisit for years.

All installed & lovely.

Then, when I thought I'd try the HL2 demo. That too is Steam protected (which seems a little overcautious to me but there you go).

Only thing is, it wants to reinstall Steam: Will that kill my existing authorisations? I looked around the Valve support site but it doesn't seem to have an answer for me. I dare not try a PC specific support site because I'm pretty sure the answer will read "LOL j00 am teh lamerz. Macs B sUx0rz" or somesuch.

What do you lot think? I'm not sure whether the game authorisations live as cookies on the PC or in some form on the Valve server..

The way steam works is that it links all your steam games to one steam ID. You can login to steam from any computer, it'll update, and recognize which games you own. You can then download them to the computer that you're using. You can't login from multiple computers at one time. Steam also auto-updates whenever it's connected to the internet, and there's an update available.

The HL1 I have included a Steam install. The only wrinkle was that the HL2 demo seemed to want to reinstall steam from scratch: looks like there's a maximum of how much damage I can do by pressing 'OK'.